[whatwg] overflow of seamless iframes

Tue Feb 17 19:36:34 PST 2009

What I mean was that actually, before html5, the iframe doesn't adjust
automatically its height to its content, and that could be fixed by
setting/allowing the CSS property "overflow: visible".

But if I understood correctly the current text in the spec, now this is the
default behaviour. Is that correct?

--
Samuel Santos
http://www.samaxes.com/

On Wed, Feb 18, 2009 at 2:02 AM, Ian Hickson <ian at hixie.ch> wrote:

> On Tue, 19 Aug 2008, Ian Hickson wrote:
> > On Mon, 18 Aug 2008, Robert O'Callahan wrote:
> > > On Mon, Aug 18, 2008 at 6:45 PM, Ian Hickson <ian at hixie.ch> wrote:
> > > > On Mon, 18 Aug 2008, Robert O'Callahan wrote:
> > > > > On Mon, Aug 18, 2008 at 4:40 PM, Ian Hickson <ian at hixie.ch> wrote:
> > > > > > On Mon, 18 Aug 2008, Robert O'Callahan wrote:
> > > > > > > Ian wrote:
> > > > > > > >
> > > > > > > > Note that the default width and height are adjusted for
> > > > > > > > seamless iframes to match the width that the element would
> > > > > > > > have if it was a non-replaced block-level element with
> 'width:
> > > > > > > > auto', and the height of the bounding box around the content
> > > > > > > > rendered in the iframe at its current width, respectively.
> > > > > > >
> > > > > > > "The bounding box" is a bit ambiguous. If the content overflows
> > > > > > > vertically above the iframe's viewport, does that contribute to
> the
> > > > > > > height of the bounding box?
> > > > > >
> > > > > > As far as I can tell there is no ambiguity to the concept of the
> > > > > > bounding box of the content in the canvas, especially given the
> way
> > > > > > the initial containing block is forced to zero height.
> > > > >
> > > > > What's the answer to my question then? Should I have been able to
> derive
> > > > > it somehow?
> > > >
> > > > I don't understand the question. How does the viewport affect the
> bounding
> > > > box?
> > >
> > > Suppose the iframe's document is
> > > <body style="position:relative; top:-100px; height:500px;
> > > background:yellow;"></body>
> > > What's the height of the bounding box? 400px or 500px?
> >
> > 500px.
>
> To make sure this is clear even in the face of scrolling and fixed
> positioned content and so forth, I've adjusted the spec to say:
>
> # In visual media, in a CSS-supporting user agent: the user agent should
> # set the intrinsic height of the iframe to the height of the bounding box
> # around the content rendered in the iframe at its current width (as given
> # in the previous bullet point), as it would be if the scrolling position
> # was such that the top of the viewport for the content rendered in the
> # iframe was aligned with the origin of that content's canvas.
>
>
> On Tue, 19 Aug 2008, Robert O'Callahan wrote:
> > > > >
> > > > > If we allow the contents to flow out of the box, then we also
> > > > > allow blog comments to start overlapping other content on the
> > > > > page.
> > > >
> > > > Yeah, although setting overflow:hidden on the iframe could be used
> > > > to prevent that.
> > >
> > > Fair enough. In that case I'd rather we had this in the UA stylesheet:
> > >
> > >   iframe[seamless][sandbox] { overflow: hidden ! important; }
> >
> > I'd suggest having that except without !important.
> >
> > But never mind about this issue anyway. I think we can live without it.
>
> Ok. I have not changed the spec to allow content in seamless iframes to
> overflow out of their frames.
>
>
> On Tue, 19 Aug 2008, Samuel Santos wrote:
> >
> > It's not clear to me why "iframe { overflow: visible; }" won't do
> > anything.
>
> There is no difference here with respect to the <iframe>'s browsing
> context being a regular browsing context. Browsing contexts don't render
> outside their edges.
>
>
> --
> Ian Hickson               U+1047E                )\._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
>
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